Download Bio Exam 4 Study Guide- Question Format Fatty acid Synthesis

Bio Exam 4 Study Guide- Question Format
Fatty acid Synthesis
1. Where does fatty acid synthesis mainly occur?
a. Liver
2. What is the starting material for FA Synthesis?
a. Acetyl CoA
3. What reducing cofactor is used in the liver FA synthesis process?
a. NADPH
4. FA synthesis occurs by adding two addition carbon units. This leads to predominantly what type
of FA chains?
a. Even numbered chains
5. Where does the Acetyl CoA come from?
a. Glycolysis
6. How is Acetyl CoA taken out of the inner mitochondrial membrane?
a. It is condensed with OAA to form CITRATE, which can be transported out of
mitochondrion
7. Once on the outside the mitochondria, how is citrate broken down into OAA and Acetyl CoA?
a. Citrate lyase
8. What happens to the OAA produced?
a. It is reduced to malate, and then further to pyruvate
9. What is significant about this OAA to pyruvate reaction pathway?
a. It produces NADPH
10. If a patient eats a chronic amount of carbohydrate, this OAA to malate, to pyruvate pathway will
increase. What is the measurable enzyme that will also increase in production?
a. Malic enzyme
11. Where is NADPH also made?
a. Pentose phosphate pathway
12. What is the first step once Acetyl CoA is in the cytoplasm?
a. Acetyl CoA to Malonyl CoA by using ATP, Biotin, and CO2
13. What enzyme produces Malonyl CoA?
a. Acetyl CoA carboxylase
14. What is so important about this preemptive step?
a. It is the RLS and is irreversible
15. Why is it the RLS?
a. It commits acetyl CoA to FA synthesis
16. How many steps occur in FA synthesis?
a. 5
17. The cysteine group on the FA synthase binds to what two molecules in the first step?
a. Acetyl CoA and Malonyl CoA
18. This first step of Acetyl CoA and Malonyl CoA releases CO2, leaving the newly formed molecule
with how many carbons overall?
a. Four
19. In order to get rid of the ketone group in this four carbon chain, what molecule is used to form a
usable chain?
a. 2 NADPH
20. What is released when the ketone group is converted to an alcohol group?
a. An H2O molecule
21. What molecule binds, again releasing CO2, and adding two carbons?
a. Malonyl CoA
22. What steps will again follow the binding of Malonyl CoA?
a. 2 NADPH used to get rid of the ketone group
23. The condensation step of Malonyl CoA and Acetyl CoA becoming one happens where?
a. ACP
24. Explain the final step in FA Snythesis?
a. Thioesterase cleaves palmitoyl ACP to release the fatty acid
25. Palmitate is rapidly converted to what by acyl CoA synthetase?
a. Palmitoyl CoA
26. The elongation and desaturation enzymes are localized where for FA synthesis?
a. Endoplasmic Reticulum cytoplasmic face
27. Once you get past 16 carbons (palmitate), which enzymes are used to facilitate FA synthesis?
a. Elongase enzymes
28. What are Monounsaturated fats (MUFA)?
a. One double bond
29. What are Polyunsaturated Fats (PUFA)?
a. Unsaturated FA containing more than one double bond
30. Single bonded chains are catalyzed into double bonded molecules through what process?
a. Desaturases catalyze double bond formation by using NADH and O2.
31. Where can desaturases place the double bond? Where can they not?
a. Between carbonyl carbon and carbon 10. Not between carbon 10 and terminal methyl
group carbon.
32. Because desaturases can’t produce double bonds past carbon ten, what are the main enzymatic
molecules that cannot be synthesized?
a. Eicosanoids
33. In a simple way, explain how we make those eicosanoids, like arachidonic acid.
a. Start with an essential FA that has been ingested, introduce the DB we can make,
lengthen the chain to move the DB where we want it, and continue to add DB if needed
34. In comparison to FA oxidation, what is the location of FA synthesis?
a. Ox: mitochondria Syn: cytosol
35. In comparison to FA oxidation, what is the thioester carrier in FA synthesis?
a. Ox: acetyl CoA Syn:maolonyl CoA
36. In comparison to FA oxidation, what type of enzymes are used in FA synthesis?
a. Ox: Individual Enzymes Syn: Enzyme complex
37. In comparison to FA oxidation, what is the electron carrier for FA synthesis?
a. Ox: NADH Syn: NADPH
38. How are the newly formed FAs protected from beta oxidation in the mitochondria?
a. The build up of Malonyl CoA inhibits the CPT1 transferase, making sure the new FAs
stay outside of the mitochondria
39. What hormones regulate fatty acid metabolism?
a. The same hormones that regulate blood glucose levels
40. Which hormone acts as an allosteric promoter of acetyl CoA carboxylase and thus FA sythesis?
a. Insulin
41. What two molecules act as allosteric inhibitors of acetyl CoA carboxylase, and thus FA synthesis?
a. Glucagon and epinephrine
42. In what two ways does insulin activate FA synthesis and protect degradation?
a. Dephosphorylating acetyl CoA carboxylase; dephosphorylating lipase, preventing TG
hydrolysis
43. What other two forms of regulation does FA synthesis have?
a. Feed forward and feedback inhibition
Synthesis of TG and Membrane Lipids
1. Synthesis of phosphatidic acid starts synthesizing glycerol-3-p through what two pathways?
a. Glucose to G-3-p using DHAP and NADH; glycerol to G-3-p using ATP in the liver
2. What enzyme is used to breakdown glucose into G-3-p?
a. G-3-P Dehydrogenase
3. Adipose cannot produce G-3-P from glucose, and subsequently always breaks down glycerol.
Why is this?
a. It lacks the G-3-P Dehydrogenase enzyme.
4. What are then added by acyltransferases to the G-3-P molecule?
a. Acyl groups
5. Saturated FAs are added where preferentially?
a. C-1
6. Unsaturated FAs are added where preferentially?
a. C-2
7. This two acyl group additions produce what?
a. Phosphatidic acid
8. How is phosphatidic acid then converted to diacyl glycerol (DAG)?
a. Carbon 3 is dephosphorylated
9. What then happens at carbon 3 to complete the TG synthesis?
a. A third FA is attached to the c-3
10. What is the packaging process for TGs in the liver?
a. They are packaged into VLDLs, processed in the golgi and secreted into the blood
11. What is the main destination for TGs?
a. Adipose tissue for storage and muscle for energy use
12. What processing is similar to VLDL processing in the liver?
a. Chylomicron processing in the intestine
13. What are the differences between chylomicrons and VLDLs?
a. Chlyos:ApoB-48 VLDLs:ApoB-100
14. Storage of TG in adipose tissue happens under what signal?
a. Insulin
15. TG in blood are hydrolyzed to FA and glycerol by what enzyme?
a. Lipoprotein lipase (LPL)
16. Where is LPL found and synthesized?
a. Found on outer surface of plasma membrane of cells lining the capillary tissues;
synthesized in adipose cells and secreted into capillaries of adipose tissue in response to
insulin
17. FAs liberated by LPL are taken up by what cells?
a. Adipose cells
18. Adipose cells need these free FAs especially because why?
a. They don’t have glycerol kinase to breakdown glycerol, so they must breakdown FA
instead
19. Degradation of TG happen under what signal?
a. Glucagon
20. FAs are cleaved from the TG by what enzyme?
a. Lipases
21. How are the lipases signaled to activate?
a. Increased glucagon signals increase cAMP levels, activating protein kinase A. Protein
kinase A then phosphorylates a hormone-sensitive lipase to turn on lipases
22. Degrading of TG produces what, which can then be released into the blood?
a. FA and glycerol released into blood
23. How are FAs carried in the blood?
a. By albumin
24. What molecules are considered membrane lipids?
a. Glycerophospholipid, sphingomyelin, cerebroside or ganglioside, and plasmalogen
25. Describe glycerophospholipid.
a. Glycerol backbone with two fatty acids and one phosphate head group
26. Describe sphingomyelin.
a. Sphingosine backbone with one fatty acid and one phosphate choline group
27. Describe cerebroside or ganglioside.
a. Sphingosine backbone with one fatty acid and one carbohydrate
28. How are glycerophospholipids synthesized from phosphatidic acid?
a. Head groups are activated by CTP along with diacylglycerol
29. How can the liver interconvert phospholipids?
a. By using the methyl donor S-adenosyl-methionine (SAM)
30. What two parts can sphingolipid synthesis be divided into?
a. Formation of ceramide; conversion of ceramide to sphingomyelin and glycolipids
31. What two molecules form 3-ketosphinganine?
a. Serine and palmitoyl CoA
32. 3-ketosphinganine then forms what through 3 reactions?
a. Ceramide
33. Glycerophospholipids are degraded through hydrolyzation by what enzymes?
a. Phosphlipases
34. Phospholipase C cuts where?
a. Between carbon three and the head group
35. Phospholipase D does what?
a. Releases the free base
36. Sphingolipids are degraded by what enzymes?
a. Lysosomal enzymes
Cholesterol Metabolism & Blood Lipoproteins
1. What are some functions of cholesterol?
a. Stabilizes cellular membranes, precursor for bile salts and steroids, precursors of
cholesterol can be used for making ubiquinone, dolichol, and cholecalciferol
2. Where in the body is cholesterol synthesized?
a. Liver and intestine
3. What is the starting material of cholesterol?
a. Acetyl CoA
4. What else can be a source of cholesterol?
a. Dietary sources, especially animal products
5. What is the first step of cholesterol synthesis?
a. Two acetyl CoA come together to form acetoacetyl CoA. Then a third acetyl CoA is
added to form HMG-CoA
6. What is the commitment step of cholesterol synthesis?
a. HMG-CoA to Mevalonate by use of HMG-CoA reductase and 2 NADPH
7. Where does cholesterol synthesis occur?
a. In the cytosol, but on the cytoplasmic face of the ER
8. Where is the acetyl CoA for cholesterol synthesis made?
a. Mitochondrial matrix and transported into the cytosol by the citrate transport system
9. In the FED state, what two molecule productions are activated?
a. FA and cholesterol
10. What is the first committed step and RLS of cholesterol synthesis?
a. HMG-CoA to Mevalonate
11. What is the overall, entire reaction of cholesterol synthesis?
a. HMG-CoA to Mevalonate to Isoprene. Isoprene conjugations to Squalene, then to
cholesterol.
12. Where is the site of regulation of cholesterol synthesis?
a. HMG-CoA Reductase step
13. How is HMG-CoA Reductase regulated short term?
a. By phosphorylation and dephosphorylation by AMP.
14. When AMP is high, and ATP low, what happens to HMG-CoA reductase?
a. It is phosphorylated and decreased in activity
15. What is the long term regulation of HMG-CoA reductase?
a. Modification of the enzyme levels at the DNA/mRNA level within the cell
16. Does insulin increase or decrease cholesterol synthesis?
a. Increase
17. What is the primary means to control cholesterol synthesis?
a. Control HMG-CoA reductase through transcriptional control
18. What does SREBP do for cholesterol synthesis?
a. Upregulate enzymes and factors for cholesterol synthesis
19. What do SCAP and S2P do for cholesterol synthesis?
a. Sense cholesterol levels and stimulate SREBP production
20. What is a quick way to remove HMG-CoA reductase from the pathway to down regulate
cholesterol synthesis?
a. Proteolytic degradation
21. When effect does glucagon have on HMG-CoA-Reductase?
a. Stimulates phosphorylation, which turns it off
22. When is HMG-CoA reductase phosphorylated?
a. When you have low ATP, glucagon present, sterol level is high, and when there’s high
AMP
23. What is the intermediate compound between squalene and cholesterol?
a. Lanosterol
24. What process helps increase the solubility and hydrophobicity of cholesterol in lipoproteins?
a. Cholesterol esterification by adding a fatty acid to the cholesterol molecule by LCAT and
ACAT
25. Where are LCAT and ACAT located within the body?
a. LCAT-blood. ACAT-cells
26. What is the main function of LCAT?
a. Esterify cholesterol associated with HDL in the blood
27. What is the main function of ACAT?
a. Esterify cholesterol in the cells to store cholesterol for steroid synthesis
28. How is cholesterol transported in the blood?
a. Chylomicrons and LPL from the liver
29. What are the four main functions of cholesterol?
a. Bile salts, steroid hormones, membranes, blood lipoproteins
30. What are VLDL lipoproteins and where are they made?
a. A package of TGs and cholesterol; produced in liver
31. When LPL acts on VLDL to degrade TG, what is produced?
a. IDL is produced
32. When IDL is degraded further, IDL becomes what?
a. LDL
33. What are HDLs and what is the composition of HDL?
a. The good cholesterol, has more cholesterol esters than cholesterols and little TG
34. What is the RLS of bile salt synthesis?
a. Incorporating an OH group into cholesterol to form 7-hydroxycholesterol
35. What is cholic acid classified as?
a. Primary bile salt
36. What are the two secondary bile salts?
a. Deoxycholic acid and lithocholic acid
37. What are all steroid hormones derived from?
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a. Cholesterol
What are some steroid hormones?
a. Progesterone, aldosterone, cortisol, estradiol
What are the four lipoproteins?
a. Chylomicrons, VLDL, LDL, HDL
What is the main cholesterol transport lipoprotein?
a. LDL
Chylomicrons are high in what?
a. TG
What is the lipoprotein with the next highest amount of TG?
a. VLDL
LDL is high in what?
a. Cholesterol esters
HDL is high and low in what?
a. High protein, low density
Explain ApoB-48.
a. Primarily in the intestine. Assembly of chylomicron
Explain ApoB-100.
a. Primarily in the liver. Assembly of VLDL
Explain ApoC-II.
a. Primarily in the liver. Activator of LPL
Explain ApoE.
a. Primarily in the liver. Picks up the remnants
What are some ways cholesterol can self regulate itself?
a. Inhibit LDL receptor synthesis, inhibit HMG-CoA Reductase synthesis, promote
cholesterol esterification, decrease cholesterol synthesis at transcriptional level
Explain Atherosclerotic plaque formation.
a. Minor damage to BV wall, Macros recruited and uptake LDLs. Macros fill with fat and
form FOAM cell. Foam cells accumulate and aggregation occurs forming clot.
Which enzyme catalyzes the committed step of cholesterol synthesis?
a. HMG-CoA saturase
b. HMG-CoA isomerase
c. HMG-CoA oxidase
d. HMG-CoA reductase
D
What is the starting material for cholesterol synthesis?
a. Acetyl CoA
b. Citrate
c. 3-hydroxy-3-methylglutaryl CoA
d. Squalene
A
The conversion of HMG CoA to mevalonate
a. requires NADH and H+
b. is the committed step for cholesterol synthesis
c. is stimulated by cholesterol
d. is a step in the synthesis of ketone bodies
B
54. Blood lipoproteins are classified by what properties?
a. Function, based on the tissues with which they interact
b. Lifetime, based on how long they circulate to carry out function
c. Density, based on the ratio of lipid to protein
d. Size, based on the parts of the circulation in which they function
C
55. Why does cholesterol regulate the number of LDL receptors on the cell surface?
a. To control the number of LDL particles that are synthesized by the cell.
b. To control the entry of cholesterol into the cell via LDL
c. To control the entry of cholesterol precursors into the cell via LDL
d. To control the release of cholesterol from the cell via LDL.
B
56. Familial hypercholesterolemia is a disease that involves defective LDL cellular receptors, such
that the cells do not take up LDL at a normal rate. Which of the following would NOT be a result
of this disease?
a. increased blood LDL levels
b. increased synthesis of cholesterol in cells
c. fatty deposits in coronary arteries and elsewhere
d. increased endocytosis of LDLs. ***
The dreaded Protein Nutrition
1. What is the role of protein in the body?
a. Maintenance and growth of the body tissues. Involved in structure, enzymes, hormones,
transport, and immunoproteins
2. Where does protein digestion begin?
a. In the stomach
3. Where does most of protein digestion occur?
a. Upper portion of the small intestine, but continues throughout the GIT
4. What is the end result of protein digestion?
a. Amino acids and small peptides that are transported via the portal vein to the liver
5. How do proteins differ from carbs and lipids?
a. They contain Nitrogen
6. Plasma proteins that transport, such as albumin, function in what manner?
a. Exert osmotic pressure needed to maintain fluid in a vascular space
7. Protein is our ___ ____ energy store at 4 Kcal/g.
a. Second largest
8. What are the nine essential AA?
a. Phenylalanine, valine, threonine, tryptophan, isoleucine, methionine, histidine, (a),
leucine, lysine (PVT TIM HaLL)
9. What is meant by conditionally essential AA?
a. The need for that AA increases bc synthesis cannot meet the metabolic need
10. An AA Score of 1 would indicate what about that particular protein food source?
a. That protein is fully digestible
11. Because vegetable protein isn’t initially broken down like meat protein with marinades and
heat, vegetables tend to be less efficient and have a lower AA score. How can this be
counteracted?
a. The vegetable protein meals must be complimented together within a few hours. So
whichever AA is lacking from one source, another food needs to be eaten that is rich in
those originally lacking AA to make a “complete protein”.
12. Beans are low in __ but high in __. (specific AA).
a. Methionine, lysine
13. Corn is low in __, but high in ___. (specific AA).
a. Lysine, methionine
14. Lacto-ovo-vegetarians and lactovegetarians are both at risk for what deficiency?
a. Iron
15. What diet is at risk of calcium, zinc, iron, and vitamin B12 deficiencies?
a. Vegans
16. How much protein do healthy adults need daily?
a. 0.8g protein/kg
17. How much protein do infants need daily?
a. 1.5 g protein/kg
18. How much protein do 1-3 yo need daily?
a. 1.1 g protein/kg
19. How much protein to 4-13 yo need daily?
a. 0.95 g protein/kg
20. How much protein to 14-18 yo need daily?
a. 0.85 g protein/kg
21. How much protein do pregnant women need daily?
a. 1.1 g protein/kg
22. How much protein do lactating women need daily?
a. 1.3 g protein/kg
23. How much protein do critically ill patients need daily?
a. 1.25-2.0 g protein/kg
24. How much protein do people healing from decubitus ulcers need daily?
a. 1.2-2.0 g protein/kg
25. How much protein do endurance athletes need daily?
a. 1.2-1.4 g protein/kg
26. How much protein do strength training athletes need daily?
a. 1.2-1.7 g protein/kg
27. How much protein do resistant training athletes need daily?
a. 1.2-2.0 g protein/kg
28. What is the conversion of kg to lbs?
a. 2.2 lbs=1 kg
29. What two molecular markers are seen in patients with inflammation?
a. CRP, HsCRP
30. Low creatinine levels would be indicative of what?
a. Low protein levels and possibly malnourishment
31. High protein diets often contribute to what?
a. Dehydration
32. Marasmus is what?
a. Protein and energy deficiency
33. Kwashiorkor is what?
a. Protein deficiency
34. Kwashiorkor leads to what in children?
a. Ascites= abdominal swelling
35. Stunting is an indication of what? This can be seen by the child being how many standard
deviations from the normal?
a. Protein deficiency; 3
36. In adults, protein malnutrition is known as what and is often overlooked?
a. PEM= protein energy malnutrition
37. In a rehab unit, you have a 39 yr.. s/p MVA who is a quadriplegic and he has developed 2 stage
IV decubitus on his bottom. He is 180 lbs. (81.8Kg) and is 6 feet tall. What is his protein need
and calorie need?
a. 164g, 2870 Kcal
b. 66g, 2560kcal
c. 90g, 2870 kcal
d. 82g, 2050 kcal
A
38. You are seeing a 31 year old healthy pregnant women. She wants to be sure she is eating
enough protein. Her weight is 155lbs (70.4kg). She can meet her protein needs with which of
the following daily intake? Note grams of protein are listed in (g).
a. 1 c oatmeal and 1oz nuts 1 orange, 1c milk(18g ); 1 c chili and 6 crackers (17g), and
salad; 1pc veggie pizza and 1 apple(16g).
b. 2c rice Krispies and 1c milk (14g); 1 pb & J sandwich, 12oz sprite, 1c grapes (13g); 1c
spaghetti with meat balls, salad, 1c milk (27g); 1 bag popcorn (4g).
c. 2 eggs. 1pc butter toast, 8oz OJ, bacon 2pc (22g): 2 protein bars and water (40g);1c Chex
mix and 4oz yogurt (14g); 12oz milk shake (12g);1 hot dog with chili (16g).
d. 2 corn tortillas, 1c organic pintos, salsa 1/3c, 1c soy milk (28g); 1 granola bar (10g);
11/2c quinoa salad, 1c yogurt, 8oz tea ( 25g); 1 ice cream sandwich (9g); 1 orange, 1
veggie wrap, 1 bag potato chips (6g)
D
Eicosanoids
1. What is the starting molecule for all eicosanoids?
a. Arachidonic Acid
2. What are the three most common eicosanoids?
a. Prostaglandins, thromboxanes, leukotrienes
3. Describe what is significant about eicosanoids?
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a. Produced in small amounts and have a VERY short half-life because they are among the
most potent signaling compounds we make. They are made locally at the tissue and act
locally
What enzyme takes arachidonic acid to leukotrienes?
a. Lipoxygenase
What enzyme takes arachidonic acid to prostaglandins?
a. Cyclooxygenase
What is essential in your diet in order to make arachidonic acid, and subsequently eicosanoids?
a. PUFAs
What is the role of phospholipase A2?
a. It cleaves PUFA from phospholipids
What blocks phospholipase A2, resulting in inhibition of prostaglandin production?
a. Steroidal anti-inflammatory agents
What is the function of NSAIDs?
a. Block prostaglandin formation by irreversibly inhibiting cyclooxygenase (COX)
Where are the receptors for eicosanoids and what does this allow them to do?
a. On the membrane of the specific cell. This allows them to have very specific intracellular
functions.
For the most part, eicosanoids act through what two ways in the cell?
a. Increasing cAMP and increasing CA2+ levels within the cell
PGE2 is associated with what three functions in the body?
a. Pregnancy, abortion, and erection
PGI2 is associated with what three functions in the body?
a. Bronchial dilation, scleroderma, and pulmonary hypertension
Thromboxane A2 is associated with what function in the body?
a. Platelet aggregation
LTB4 is associated with what function in the body?
a. Acute respiratory distress
LTD4 is associated with what two functions in the body?
a. Asthma, inflammatory bowel disease
In humans, what three fatty acids predominate?
a. Omega-3, 6, and 9
DHA, EPA, and DPA all inhibit what?
a. Inflammation
What is the optimal ration of ω-3 and ω-6 in order to maintain pro-inflammatory response from
the eicosanoids?
a. 1:1 ratio
What are we seeing in today’s normal dietary intake, which can ultimately lead towards proinflammatory responses?
a. High ω-6 FAs
Urea Cycle
1. What is the main function of the liver?
a. Ammonia metabolism
2. Ammonia concentration of ___ is ten times that of plasma concentrations.
a. Liver
3. Dietary protein breakdown can lead to the production of what?
a. Nitrogen
4. NH3 is what?
a. Ammonia
5. NH4+ is what?
a. Ammonium
6. What is the ratio 100:1 standing for in relation to Nitrogen?
a. NH4+:NH3 or ammonium: ammonia
7. What is a negative nitrogen balance?
a. Excretion exceeds intake
8. What is a positive nitrogen balance?
a. Intake exceeds excretion
9. What is the major process of removing nitrogen from amino acids?
a. Transamination
10. What occurs in transamination?
a. Nitrogen is transferred as an amino group from an AA to α-KG to form glutamate
11. What catalyzes transamination reactions?
a. Transaminases and PLP
12. What is PLP?
a. Vitamin B6
13. All AA can undergo transamination except what two?
a. Lysine and threonine
14. When liver cell damage occurs, what two enzymes can leak into the blood?
a. AST and ALT
15. What are three main sources of NH4+ in the human body?
a. Recycling of purine in the brain and muscle, AA deaminations (transamination), flora in
gut produce N naturally
16. Explain how glutamate goes to α-KG.
a. Oxidative deamination by glutamate dehydrogenase. Releases ammonium ions
17. What is used to deaminate glutamate? To reaminate glutamate?
a. NADH; NADPH
18. What does serine dehydratase do?
a. Takes serine to threonine by deamination
19. What does asparaginase do?
a. Takes asparagine to aspartate by deamination
20. What does glutaminase do?
a. Takes glutamine to glutamate by deamination
21. All three of these deamination reactions release NH4+ for what to use?
a. Urea cycle
22. Serine dehydratase is dependent on what?
a. PLP
23. What cycle in the brain and muscle produces NH4+?
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a. Purine nucleotide cycle
Where is another source of N from the body?
a. Bacteria in the intestinal tract convert urea to ammonia and release ammonia from AA
*What is the first step in the Urea cycle and where does it occur?
a. NH4+ and bicarbonate are condensed using 2 ATP to form carbomyl phosphate;
mitochondrial matrix
What is the enzyme that takes bicarb and NH4+→carbomyl phosphate?
a. Carbamoyl phosphate synthetase I (CPS I)
What do the first and second ATP do in this reaction?
a. 1st: conjugates bicarb. 2nd: donates P
What happens to the carbamoyl phosphate next?
a. It combines with Ornithine to form CITRULLINE in the second urea cycle step
What enzyme is used to combine ornithine and carbamoyl phosphate, producing Citrulline?
a. Ortnithine transcarbamoylase
What happens to Citrulline next?
a. It leaves the mitochondria and goes to the cytosol, through a citrulline/ornithine
antiport. It then combines with aspartate to form ARGINOSUCCINATE
What is used in the Citrulline + Aspartate → Arginosuccinate reaction?
a. ATP and Arginosuccinate synthetase
What happens to Arginosuccinate next?
a. It splits into Fumarate and Arginine.
What is used in the Arginosuccinate → Fumarate + Arginine reaction?
a. Arginosuccinate lyase
What happens to Arginine next?
a. It combines with H2O to form Urea and Ornithine
What is used in the Arginine + H2O → Urea + Ornithine reaction?
a. Arginase
Where does the Ornithine go once produced?
a. Its transported back into the mitochondria in the Ornithine/citrulline antiport
What other cycle does the Urea cycle depend on?
a. TCA cycle
What acts as an allosteric effector, to increase the Urea Cycle production?
a. High Arginine produces NAG, which stimulates CPS1 to begin the Urea cycle
What other two forms of regulation act on the Urea Cycle?
a. Substrate availability- enzymes and substrate must be present in sufficient amts
Induction: prolonged N conditions cause high amts of urea cycle enzyme production to
help handle the increased N load
What are two cases that would produce high Nitrogen load?
a. High protein diet and prolonged fasting
What is glucagon’s effect on the Urea Cycle?
a. It increases synthesis of CPS1, to help deal with the increased N production during
fasting
Explain why urea cycle is low in the Fed state.
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a. AAs are used for protein synthesis, so deamination is not needed, which leads to low N
levels
Describe the Urea cycle in the Fasted State.
a. At 12 hours, gluconeogenesis is high, so there is a very high amount of N produced, thus
the Urea Cycle is very high at first. AA use decreases as fast continues, so Urea cycle
decreases
Why is there a high amount of Nitrogen produced when gluconeogenesis is high?
a. AAs are deaminated to provide carbon skeleton for glucose synthesis, producing lots of
Nitrogen
What happens when CPS I is deficient?
a. Hyperammonemia
What happens when Ornithine transcarbamoylase is deficient?
a. Increased ammonia and orotic acid in the blood
What happens when Argininosuccinate synthase is deficient?
a. High citruline levels in the blood
What happens when argininosuccinate lyase is deficient?
a. Elevated citruline and argininosuccinate
What happens when Arginase is deficient?
a. High arginine levels in blood, and low urea levels
What is the most common deficiency involving the Urea Cycle?
a. Ornithine transcarbamoylase deficiency
What happens when liver function is impaired?
a. High levels of ammonia= ammonia toxicity
How do high levels of ammonia effect the brain?
a. High ammonia → high glutamine → low α-KG and low glutamate→ neuro issues and
Hepatic Encephalopathy
What are three ways to prevent ammonia toxicity?
a. Reduce protein intake, reduce bacterial source of ammonia, remove excess AA
What does Benzoate do?
a. Binds glycine to form benzoylglycine
What does Phenylacetate do?
a. Binds glutamine to form phenylacteylglutamine
What do Benzoate and Phenylacetate act to do overall?
a. Remove excess AA
Infant presents with low orotate, low citruline, low arginine, high ammonia. What is the enzyme
deficiency?
a. CPS I
Infant presents with high citruline, low arginine, high ammonia. What is the enzyme deficiency?
a. Argininosuccinate synthetase
Infant presents with high arginine and moderately high ammonia levels. What is the enzyme
deficiency?
a. Arginase
Infant presents with high orotate, low citruline, low arginine, and high ammonia levels. What is
the enzyme deficiency?
a. OTC
61. Infant presents with high citruline, low arginine, and high ammonia levels. What is the enzyme
deficiency?
a. Argininosuccinase
AA Synthesis and Degradation
1. Glucose breaks down into what?
a. Phosphoglycerate
2. Phosphoglycerate breaks down into what?
a. Pyruvate and serine
3. Serine breaks down into what?
a. Glycine, and cysteine (with the addition of methionine)
4. Pyruvate breaks down into what?
a. Alanine, Acetyl CoA, and Oxaloacetate
5. Oxaloacetate breaks down into what?
a. Aspartate
6. Aspartate breaks down into what with the addition of glutamine?
a. Asparagine
7. OAA and Acetyl CoA combine to form what?
a. Citrate
8. Citrate breaks down into what?
a. Isocitrate
9. Isocitrate breaks down into what?
a. α-KG
10. α-KG breaks down into what?
a. Glutamate
11. Glutamate breaks down into what?
a. Glutamine and glutamate semialdehyde
12. Glutamate semialdehyde breaks down into what two molecules?
a. Proline and arginine
13. Phenylalanine breaks down into what?
a. Tyrosine
14. Why does PKU treatment create a ‘conditional essential AA’?
a. Phenylalanine is restricted in the diet, so tyrosine is no longer produced. So now
tyrosine is a conditional essential AA. Wasn’t originally needed, but because it isn’t able
to be produced, it is now essential.
15. What are the S-containing AA that aren’t essential, but can only be produced from eachother?
a. Methionine, homocysteine, cysteine
16. Similarly, what is the aromatic pair?
a. Phenylalanine and tyrosine
17. Similarly, what is the N group of AA produced in the urea cycle?
a. Arginine, ornithine, and citrulline
18. Nonessential AA for mammals are usually derived from intermediates in what two pathways?
a. Glycolysis and TCA
19. In the reaction of glycine to serine, what is the enzyme that takes 3-phosphoglycerate to serine?
a. 3-phosphoglycerate dehydrogenase
20. How does 3-phosphoglycerate dehydrogenase work?
a. It is induced when serine levels are low, it is repressed when serine levels are high. Self
regulates.
21. What two intermediates are required for serine → glycine?
a. Tetrahydrofolate and PLP
22. If methionine is low, what AA becomes conditionally essential?
a. Cysteine (serine + Methionine → cysteine)
23. Cysteine inhibits what enzyme, serving as a product inhibitor or negative feedback system?
a. Cystathionine β-synthase
24. What is Cystathionuria?
a. Build up of cystathionine in the urine
25. What are the two forms of Cystathionuria?
a. Premature infants: cystathionase lyase is low at birth but increases as they age.
Adults: cystathionase lyase deficiency, or low PLP/Vitamin B6
26. Serine and glycine are especially important in what synthesis pathway?
a. Membrane synthesis
27. What serves as an important intermediate in many bodily functions?
a. Glycine
28. What is the major gluconeogenic AA?
a. Alanine
29. Alanine → pyruvate uses PLP and what enzyme?
a. ALT
30. OAA → Aspartate uses PLP and what enzyme?
a. AST
31. What is a key marker for liver damage?
a. AST in the blood
32. Aspartate + glutamine (with ATP and asparagine synthetase)→ ?
a. Asparagine
33. To degrade asparagine back to aspartate, what enzyme is needed?
a. Aspariginase
34. Aspariginase is used in what other way than simple asparagine degradation?
a. Chemotherapy in leukemia
35. In order to go from glutamate → glutamine, what enzyme is needed?
a. Glutamine synthetase
36. What is the reverse reaction catalyzed by (glutamine→glutamate)?
a. Glutaminase
37. What organ function is glutaminase important for?
a. Kidney function. It raises urine pH
38. What enzyme is used in Phenylalanine → Tyrosine?
a. Phenylalanine hydroxylase
39. What is the deficiency of phenylalanine hydroxylase?
a. Phenylketonuria (PKU)
40. How do you treat PKU?
a. Remove Phe from diet and add Tyrosine
41. Tyrosine is an important intermediate for production of what five molecules?
a. L-Dopa, Dopamine, Norepinephrine, epinephrine, thyroid hormones
42. How does classic PKU present?
a. In infants, appear normal, but neuro status gradually decreases. Mousy smelling urine
due to decreased urine
43. How does malignant PKU present?
a. Normal enzyme levels, but cofactor enzyme DHPR deficient. Diet changes do not fix
issue and patient dies within first two years of life.
44. What is Dihydropteridine Reductase (DHPR) deficiency? What is the treatment?
a. Can’t make BH4. Administer precursors of serotonin and norepinephrine
45. What are the two Ketogenic AA?
a. Leucine and Lysine
46. What are the five ketogenic and glucogenic (both) A?
a. PITTT- Phenylalanine, isoleucine, threonine, tyrosine, tryptophan
47. Alanine → ? through hydrolysis
a. Pyruvate
48. Asparagine → ? through hydrolysis
a. Aspartate
49. Aspartate → ? through hydrolysis
a. OAA
50. Glutamine → ? through hydrolysis
a. Glutamate
51. Glutamate → ? through hydrolysis
a. Alpha-KG
52. Glucogenic AAs convert to what two molecules to supply TCA?
a. Pyruvate and OAA
53. Ketogenic AAs convert to what two molecules?
a. Acetyl CoA and acetoacetate
54. What enzyme is involved in Histidine → glutamate?
a. Histidase
55. Deficiency of histidase is known as what?
a. Histidenemia
56. Histidenemia results in what increase and what two decreases?
a. Increased histamine, decreased urocanic acid and decreased alpha-KG
57. Serine → PEP →?
a. Pyruvate
58. OAA + calcium produces what in the body?
a. Kidney stones
59. An enzyme deficiency in alpha-ketoacid dehydrogenase, yielding an accumulation of the alphaketoacids would lead to what disease?
a. Maple syrup disease
60. What is the treatment of maple syrup disease?
61.
62.
63.
64.
65.
66.
67.
68.
69.
a. Restrict intake of branched chain AA
What is cystinosis?
a. A rare disorder where the cysteine transporter of lysosomal membranes is defective
Cystinosis leads to what?
a. Renal failure by age 6-12
Describe Homocystinuria Type 1.
a. Cystathionine synthase deficiency → elevated methionine and homocysteine
What is the treatment of Homocystinuria type 1?
a. High dose of vitamin B6 (PLP)
Elevated homocysteine levels increase the risk of what disease?
a. Cardiovascular disease
Explain Albinism.
a. Defect in tyrosinase so no pigments produced
Explain Alcaptinuria.
a. Defect in homogentisate oxidase. Homogentisate accumulates in the urine and
vertebrates as black pigment
Describe Tyrosinemia Type I and II.
a. Type I- deficiency in fumaryl acetoacetate hydrolase. Produces liver failure and cabbage
like odor
Type II- deficiency in TAT. Eye and skin lesions, neuro symptoms. Rx: restrict Tyr and Phe
in diet
Describe methylmalonic acidemia.
a. Deficient methylmalonyl-CoA mutase. Leads to mitochondrial stress and low ATP
production
Special products derived from AA
1. What is Glutathione?
a. GSH
2. What kind of bond does GSH have and what does this prevent?
a. Gamma-peptide bonds; attack by peptidases
3. What two things are GSH a substrate for?
a. Y-glutamyltransferase, GSH-peroxidase
4. The reaction of ROS and ascorbate produces ___. GSH reduces that same molecule.
a. Dehydro-ascorbate
5. Where is GSH synthesized and transported?
a. Synthesized by an enzyme pathway in the cytosol of nucleated cells. Transported into
mitochondria through a transporter in the inner mitochondria
6. Where is GSH present?
a. All mammalian cells except in neurons
7. What are the two main functions of creatine?
a. Reservoir of high energy phosphate
8. Creatine goes to creatine phosphate via what enzyme?
a. CPK or CK
9. High amounts of CK in blood are seen in what type of patients?
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
a. Stroke and heart attack
Creatine phosphate kicks off a phosphate and becomes what?
a. Creatinine
Creatinine is used as what for measurements?
a. Baseline for excretion levels
What is the better indication of excretion?
a. Amount of compound/amount of creatinine excreted in the urine
Serum creatinine levels indicate what?
a. Glomerular filtration rate
High serum creatinine levels indicate what?
a. Glomerular dysfunction
What is heme?
a. One ferrous ion with a tetrapyrole ring around it
What is the first step of heme production?
a. Succinyl-CoA and Glycine (with PLP) form gamma-ALA
What is significant about the first step in heme synthesis?
a. It is the RLS
How is heme regulated?
a. Production inhibition
What is vitamin B6 deficiency associated with?
a. Microcytic hypochromic anemia
What is the last step of heme synthesis?
a. Ferrochelatase which incorporates iron into heme.
Describe lead poisoning.
a. Lead inhibits the process of making heme by inhibiting gamma-ALA (first step) and
ferrochelatase (last step)
Reduced heme production leads to what?
a. Anemia and reduced energy production
What is Porphyrias?
a. Very rare inherited disorders. Deficiencies of enzymes in the heme pathway. Produces
buildup of intermediates, which leads to neuro issues and photosensitive skin lesions.
Where do we get iron?
a. Diet, especially in meat
How is iron transported in the blood?
a. Carried in transferrin, complexed with apotransferrin
How is iron stored?
a. Stored as ferritin
What do blood ferritin levels measure?
a. The amount of iron in body’s stores
What is Hemosiderin?
a. A form of ferritin complexed with additional iron. It also is a byproduct when iron is
used
When heme is recycled and broken down, what is it broken down into?
a. Bilirubin, which is carried by albumin
30. Where is bilirubin excreted?
a. Broken down and comes out as feces
31. What is the reticuloendothelial system?
a. Junction between blood and liver
32. In the reticuloendothelial system, heme is oxidized to what, which is then oxidized to bilirubin?
a. Biliverdin
33. In the liver, bilirubin is converted to what?
a. Bilirubin diglucoronide- a more water soluble compound
34. Bilirubin diglucoronide is excreted where to give feces its dark/red color?
a. Bile, and then feces
35. In plasma bilirubin, conjugated bilirubin would mean what if tested?
a. Liver conjugation is working. Bilirubin is coupled with diazonium salts
36. In plasma bilirubin, unconjugated bilirubin would mean what if tested?
a. Liver is not working correctly because the bilirubin is bound to albumin and is not
coupled with diazonium salts
37. What happens to bilirubin in the intestines?
a. Bacteria deconjugate bilirubin and convert it to urobilinogens
38. What happens to urobilinogens?
a. Absorbed in the blood and excreted in the urine
39. Where happens to most of urobilinogen?
a. It is oxidized to urobilins, giving feces its brown color
40. What are the three cases of hyperbilirubinemia and jaundice?
a. Amounts of bilirubin exceed its capacity to conjugate (increased unconjugated),
hepatocyte dysfunction (increased conjugated and unconjugated), hepatic obstruction
of drainage ducts (increased conjugated)
41. When does urine bilirubin increase?
a. Only when serum conjugated is elevated. Unconjugated doesn’t pass into urine
42. What is neonatal jaundice and what is the treatment?
a. It occurs frequently due to an immature system for conjugating and excreting bilirubin;
phototherapy which causes bilirubin to become water-soluble and able to be excreted
43. What is nitric oxide (NO)?
a. Arginine breakdown produces NO. NO is a gas that can diffuse rapidly into cells. It is a
biological messenger involved in vasodilation.
44. What does NO activate?
a. Guanylyl cyclase which increases cGMP synthesis, relaxing smooth muscle
45. What does nitroglycerin do and what can it treat?
a. It is converted into NO and dilates coronary arteries; treats angina pectoris or spasm
heart attacks
46. Arginine breakdown into NO happens by what?
a. Nitric oxide synthase
47. NO combines with oxygen to form what?
a. Nitrite
48. Nitrite is converted to what and excreted in the urine?
a. Nitrate
49. GABA is what?
a. Inhibitory transmitter and is synthesized by the decarboxylation of glutamate
50. Similarly to GABA, histidine forms what?
a. Histamine
51. Tryptophan produces what two products?
a. serotonin→melatonin
52. Catecholamines are what?
a. Dopamine, norepinephrine and epinephrine
53. Phenylalanine and tyrosine break down to what?
a. Dopamine, norepinephrine, epinephrine
54. Phenylalanine is also involved in what?
a. Production of melanins
55. What is albinism?
a. Hypomelanosis due to heritable defects in the Tyrosinase enzyme. Tyrosine cannot
produce effective levels of Melanin
Single Carbon Transfer
1. What three molecules typically transfer a single carbon?
a. Tetrahydrofolate (FH4 or THF), Vitamin B12 (cobalamin), S-adenosylmethionine (SAM)
2. What transfers the most oxidized form of carbon, CO2?
a. Biotin
3. How is FH4 produced?
a. Folate is synthesized by PABA, Glutamate and carbon rings. Folate →FH2→FH4.
4. Where do the electrons come from in FH4 production? What is the enzyme used?
a. NADPH; dihydrofolate reductase
5. Where do single carbon units typically come from?
a. Glucose in dietary carbs form serine. Serine is then the major source of one carbon units
6. What are two additional sources of 1 carbon transfer?
a. dUMP → dTMP and 5FU → FdUMP by thymidylate synthase
7. SLIDE 10**
8. Describe a folate deficiency.
a. Low folate causes high formiminoglutamate (FIGLU)
9. How is a folate deficiency detected?
a. Histidine load test
10. Folate deficiency results in an increased ? ratio.
a. Increased dUMP/dTUMP ratio
11. Folate deficiency inhibits what?
a. DNA repair because lack of dTTP….leads to DNA fragmentation
12. Folate deficiency leads to what type of anemia?
a. Macrocytic, megablastic anemia (cant replicate DNA so they are large)
13. Describe sulfa drugs.
a. Used in treatment of bacterial infections. In bacteria, folate are synthesized from PABA.
Sulfa drugs compete with PABA
14. Describe Methotrexate.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
a. Competes with FH2, inhibiting formation of dTMP from dUMP. Inhibits dyhyrofolate
reducatse Used in treatment of leukemia
How does Vitamin B12 transfer a single carbon?
a. Transfers methyl group
What is needed to digest Vitamin B12 and where is it absorbed?
a. Intrinsic factor; ileum
Lack of intrinsic factor results in what?
a. Pernicious anemia
How do you treat pernicious anemia?
a. Injection of Vitamin B12
Vitamin B12 transfers methyl group from FH4 to what…which forms what…?
a. Homocysteine, which forms methionine
Methionine transfers the carbon to what?
a. SAM, which then transfers the carbon to other molecules
B12 deficiencies precipitate what deficiency? Why?
a. Folate deficiency. Methyl trap theory-low B12 means high methylated B12, which
means high methylated folate leading to low reactive, unmethylated folate. This leads to
megaloblastic anemia
Vitamin B12 is involved in the conversion of succinyl CoA, which is used in the TCA cycle. This
means that B12 deficiency would lead to what?
a. Low to no ATP production. This also leads to major neuro issues because succinyl CoA is
needed in the myelin formation of the brain
SAM transfers its methyl group to produce what five molecules?
a. Epinephrine, creatine, methylated nucleotides, phosphatidylcholine, melatonin
After SAM transfers the methyl group, what is formed?
a. SAH
SAH is cleaved into what two molecules?
a. Homocysteine (which can be reused in methyl transfers) and adenosine
SAM synthesis requires what?
a. Methionine
S-adenosyl methionine is a donor of the
a. methyl group
b. formyl group
c. methenyl group
d. methylene group
e. all of the above
a
Sulfa drugs, used as antibacterial agents, compete with p-aminobenzoic acid (PABA) in the
synthesis of the vitamin
a. methotrexate
b. folate
c. cobalamin
d. pyridoxine
e. tetrahydrobiopterin
b
29. The inability to convert methyl-tetrahydrofolate to tetrahydrofolate (methyl trap theory) can be
caused by a deficiency in
a. vitamin B12
b. vitamin C
c. vitamin B6
d. vitamin A
e. vitamin B3
Nucleotide Metabolism
1. Purine synthesis requires what two main materials?
a. Amino acids as precursors and LOTS of ATP
2. Most purine ring synthesis occurs where?
a. Liver
3. What is the source of the ribose?
a. PRPP
4. What enzyme is used in purine synthesis?
a. PRPP synthetase
5. What is the initial product of purine synthesis?
a. IMP
6. IMP can form what two molecules? (these reactions can also be reciprocal)
a. AMP, GMP
7. What is the committed step of purine synthesis?
a. Adding glutamine to PRPP- adds an amine group and removes phosphates
8. For DNA synthesis, NDP is reduced to dNDP by what enzyme and what cofactor?
a. Ribonucleotide reductase; thioredoxin
9. Degradation of purine bases occurs where?
a. Liver
10. When degrading AMP, what enzyme is used to produce Xanthine?
a. Xanthine oxidase
11. What drug affects xanthine production?
a. Allopurinol
12. What two enzymes are used in the Purine salvage pathway?
a. HGPRT, ARPT
13. Describe gout.
a. Xanthine is converted to uric acid by xanthine oxidase. Overproduction of uric acid and
inadequate excretion of uric acid leads to gout.
14. Overproduction of uric acid is due to what two issues?
a. Over activity of PRPP synthetase and deficient HGPRT
15. What does allopurinol do?
a. Blocks xanthine oxidase which prevents high levels of uric acid
16. Synthesis of pyrimidines is from what?
a. Glutamine and aspartate
17. What enzyme is involved in the synthesis of pyrimidines?
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
a. CPS II
What is the general pathway of Pyrimidine synthesis?
a. Dihydrooratic acid → OMP → UMP
What two enzymes within the pathway are key?
a. Orotate phosphoribosyl transferase and Orotidylate decarboxylase
What is Hereditary orotic aciduria?
a. Deficient orotate phosphoribosyl transferase and orotidylate decarboxylase (OMP
decarboxylase)
How can individuals with hereditary orotic aciduria be treated?
a. Uridine, because it bypasses the enzymes and can be phosphorylated to UMP
UMP → UTP with the use of ATP. UTP + glutamine and CTP synthase produces what?
a. CTP, which can be used in RNA and DNA
How is CPS II regulated?
a. Negatively by UTP (product inhibition), and positively by ATP and PRPP
OMP Decarboxylase is regulated how?
a. Down regulated by product inhibition
CTP Synthetase is regulated how?
a. Down regulated by product inhibition
Ribonucleotide reductase requires which cofactor to take ribose to deoxyribose?
a. Thioredoxin
What enzyme is used in the dUMP → dTMP reaction?
a. Thymidylate synthase
What inhibits thymidylate synthase?
a. FdUMP (5-FU forms FdUMP. 5-FU is used in the treatment of colon cancer)
Describe pyrimidine degradation. Compare this to purine degredation.
a. Pyrimidines are just hydrolyzed to the nucleosides and P. In comparison, purine
degradation causes problems. Pyrimidine degradation does not.
What are the products of degradation of thymine and uracil?
a. Β-amino acids, CO2, NH4+
What are the products of degradation of cytosine?
a. B-amino acids, CO2, NH3
Describe Lesch-Nyhan syndrome.
a. HGPRT deficient in the salvage pathway
Intertissue relationship of AA
1. Skeletal muscle uses what for energy?
a. Branched chain AA
2. Nitrogen waste from this reaction is sent where?
a. Kidneys for excretion
3. Skeletal muscle sends what three products to the liver for gluconeogenesis?
a. AA, a-Keto acids, and Alanine
4. What does the skeletal muscle send to the brain for energy?
a. Glucogenic AA (valine and isoleucine)
5. Skeletal muscle breaks down BCAA to what?
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
a. BCAA→glutamine which is then released
What stimulates the liver to undergo fasting AA metabolism?
a. Glucagon and glucocorticoids
Liver is the main site of what AA uptake?
a. Alanine
What two AA are used as shuttles to move Nitrogen in the blood?
a. Alanine and glutamine
Kidney takes up what AA?
a. Glutamine
Glutamine is then transformed into what?
a. Glutamate
What molecule buffers the urine pH?
a. NH4+
Glutamine produces what two AA?
a. Alanine and serine
A-KG is formed from what?
a. Glutamate
Kidney releases what for blood pH regulation?
a. Bicarbonate
The reabsorption of bicarb into the kidney allows for what regulation?
a. pH regulation in the urine
Glutamine is absorbed into the gut and helps with production of what?
a. Ammonium
What is the unique function of glutamate in the brain?
a. It is a neurotransmitter, not just an AA.
The brain the net producer of what AA?
a. Glutamine
What two AA are used in the brain to make glutamine?
a. Glutamate is converted and BCAA are broken down
In the brain, glutamine can be converted to glutamate, and further to what?
a. GABA
What does the liver release into the blood after a high protein meal?
a. BCAAs
Why are BCAAs released from the liver instead of undergoing gluconeogenesis?
a. Liver doesn’t have transaminase to breakdown BCAA
What happens to Nitrogen levels in a hypercatabolic state?
a. Negative nitrogen balance
What is sepsis?
a. Systemic infection of the blood
In sepsis, AA are shuttled towards what two systems as top priority?
a. Immune system and anti-inflammation systems
Increased glucocorticoids, epinephrine, and glucagon stimulate adipose to do what in sepsis?
a. Release of FA